Sonication induced sheet formation at the air–water interface

Abstract

A hydrophobic pentadecapeptide, AGAAAA-GAVVGGLGG (1), part of the prion sequence PrP (106-127), on fresh aqueous dissolution takes a mixture of random and sheet conformations which forms a stable monolayer with a high beta-sheet content when compressed at the air-water interface. This also develops into a kinetically stabilized beta-sheet structure on sonication.

Assemblages of prion fragments: novel model systems for understanding amyloid toxicity

“…CD spectrum of PrP(119-126) (curve a) and PrP(121-127) (curve b) in 5% sodium dodecyl sulfate. a predominantly sheet conformation at the air-water interface have been previously reported (Satheeshkumar and Jayakumar, 2002). These results indicate that the presence of a lipid component leads to a stable sheet structure, with a higher lipid composition leading to a more twisted sheet conformation and indicating the interaction of lipid molecules with the peptide assemblage.…”

Transthyretin forms amyloid fibrils at physiological pH with ultrasonication

“…These denaturing conditions at the air-liquid interface of sonication-induced bubbles may destabilise and unfold proteins and facilitate amyloid fibril formation [18]. Monomeric TTR has one cysteine residue at position 10, which shows vulnerability to free radicals [19].…”

Ultrasonication-Dependent Acceleration of Amyloid Fibril Formation

“…There is a report that prion protein fragments compress at the air-water interface and form a stable β-sheet. 46 Altogether, ultrasonication, coupled with the repeated growth and collapse of microbubbles, exerts the two opposing effects on proteins. Understanding the physical mechanisms of these effects is the next challenge to clarifying the mechanisms of ultrasonication-dependent formation and breakdown of the fibrils.…”